Mega Man 9 achievements just happen to be black-and-white renditions of character sprites from the game, including all eight bosses! If partial greyscale sprites are all we can get for now, we'll take 'em! And hastily make a Mega Man 2-style character select screen out of them!
As for the achievements themselves, they "reveal" secrets like the fact that Dr. Wily is in the game. Please do not tell us you consider that a spoiler.